A spokesman for Scotland Yard said: "We are aware of an incident at the Aegon Championships on 17 June. A complaint has been made and the Metropolitan police service is now investigating. The allegation is of assault."

Nalbandian won the first set of the final but lost his temper in the second set after being broken by his Croatian opponent Marin Cilic. He kicked an advertising hoarding in front of the chair of the line judge, Andrew McDougall. The hoarding flew off its hinges and struck Mr McDougall in the shin, causing an inch-long gash from which blood started to seep.

Nalbandian was disqualified after being deemed guilty of unsportsmanlike conduct, handing the title to Cilic, and suffered further pain when he had his £36,500 prize money and 150 ranking points withdrawn. An ATP spokeswoman said: "Nalbandian automatically forfeited his prize money and ranking points due to his conduct default. A maximum €10,000 [£8,029] fine also was issued onsite by the ATP supervisor for unsportsmanlike conduct."

Despite the incident, Nalbandian said afterwards that he hoped to return to the Queen's Club next year. "This incident doesn't mean that I'm not going to come back," the Argentinian said. "I really feel good at this tournament. This is a bad situation for everybody and I really apologise for that but it doesn't mean anything to next year."

Nalbandian did, however, compound the situation by accusing the ATP, the governing body of the men's tour, of having a number of rules the players did not agree with, including forcing them to play when conditions were not fit. "Sometimes the ATP puts a lot of pressure on the players and sometimes you get injured because you play on a dangerous surface," he said. "Nothing happens, no one pays for that."

The 6,000-strong crowd sided with Nalbandian immediately after the incident, many of them unaware that the kick had caused such damage to the left leg of Mr McDougall, who needed treatment for the injury.

The tournament director, Chris Kermode, stopped short of saying Nalbandian, the No10 seed, would definitely be allowed back, but conceded that banning the player would be highly unlikely.

"Look, mistakes happen," he said. "I haven't really thought about next year, but you can ask me again in a couple of weeks. There was no way he intended to do that. It would be foolish to say he's not welcome back to this tournament. The tennis he's played this week has been phenomenal and the crowd like him. You could tell by the crowd that they wanted him to play, so you have to forgive these things and move on."

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